Igneous Rock Information

Igneous rocks are the only type of rocks that form from molten magma.



They have either an interlocking, a glassy, or a fragmental texture.

They form under the water at mid-ocean ridges; within continental rifts, in volcanic arcs and at volcanic hot spots.

 

Intrusive igneous rocks form under the Earth's surface where they make igneous intrusions such as sills, dikes, plutons and laccoliths.

Extrusive igneous rocks form above the surface where they turn into rock when lava solidifies. They can be either formed from an explosive stratovolcano or a relatively calm lava flow from a shield volcano .